Printing a color image as a monochrome print involves converting the input colors into various levels or shades of a monochrome color, such as gray. The number of colors that may be generated and displayed on a conventional monitor are typically many more times that of the number of levels of gray which a printer is able to print. In addition to the printer being unable to represent each color as a unique gray level, the color information itself is typically lost during the color conversion and subsequent printing of the monochrome image.
Conventional systems have attempted to retain color information in a monochrome print by analyzing individual pixels arranged within a halftone cell, where each arrangement represents a color or colors which have been converted to grayscale. However, this approach fails to provide reliable and sufficient retention of the color information due to inevitable dot gain that blends or obfuscates the individual pixels. This makes it difficult to determine both the number of pixels being printed as well as the particular arrangement which is being represented in the halftone cell. As a result, a wrong color or no color may be associated with a particular pixel arrangement that has been printed in a monochrome image.
The present invention addresses these and other problems associated with the prior art.